A user of a firearm often encounters different firing needs in different situations. It is therefore desirable that a singular weapon be adapted to fire different types of ammunition and to enable selection of an appropriate ammunition type depending on the particular situation. In the past, various hunting rifles were configured to combine several barrels of varying size in the form of "drop barrel bundles." Such hunting rifles offer the user the possibility of using different cartridges for different types of game. However, one significant drawback of these arrangements is that no repeating mechanism has been developed for use with the barrels of such rifles.
Repeating mechanisms, of course, are a desirable feature in rifles, particularly when used as assault weaponry. Prior attempts therefore combined a repeating rifle designed for firing conventional or normal-caliber cartridges with an additional barrel designed for large-caliber cartridges, such as buckshot cartridges. These known arrangements, however, are generally cumbersome, complicated in operation, and expensive. As a result, they have not experienced a great degree of popularity, and their use has been generally restricted to collectors and the like.
Perhaps the only weapon of this kind which has come into relatively widespread use is a standard assault rifle equipped with a grenade launcher barrel mounted thereon, an example of which is described in German patent DE 32 02 806 C2. This document describes an assault rifle barrel and firing system that is primarily utilized. A relatively short grenade launcher barrel is mounted to the distal end of the shaft portion of the rifle barrel. The grenade launcher barrel is equipped with a separate breech block and trigger assembly. This arrangement further includes a special sighting arrangement designed for use in conjunction with the grenade launcher barrel and is mounted proximate to the normal sighting arrangement for the assault rifle. This assault rifle/grenade launcher combination, however, is quite cumbersome. Due to size and weight considerations, the grenade launcher barrel must be considerably shorter than the rifle barrel. The grenade launcher reloading sequence and mechanism is likewise rather complicated.
In addition to its inconvenience in use, this arrangement also provides unsatisfactory recoil impact. Due to the significant distance separating the normal-caliber rifle barrel and the grenade launcher barrel, it is difficult to achieve optimized recoil characteristics for both barrels. For example, when the position of the normal-caliber rifle barrel is arranged so that the recoil force is transferred in a desirable manner to the shoulder of the user, the recoil force generated by the grenade launcher is transferred in an unsuitable manner. The heavy weight, inconvenient handling, and unbalanced recoil impact are principle reasons that such a combination rifle is unpopular with operators, and as a result is rarely used.
Although past efforts to combine rifle barrels of different calibers generally have produced unsatisfactory results, the need for such combination weapons remains. For example, large-caliber rifle cartridges that deploy so called "intelligent ammunition" have been developed. As used herein, "intelligent ammunition" is intended to mean a type of ammunition which, possibly in cooperation with a guidance system mounted on the weapon, automatically locks onto a target, thereby providing considerably improved targeting accuracy. If a weapon for firing such "intelligent ammunition" can be effectively combined with an assault rifle, the resulting weapon can be very versatile and very powerful.
Similarly, single triggers in weapons having a single breech and two firing pin pieces are also known in the art. In sport shooting rifles for clay pigeon shooting, for example, they are designed to permit firing of one barrel while the firing pin piece pertaining to the other barrel is automatically released. Also, a signaling pistol is known in the art where a change-over lever offers the options of firing any barrel or both barrels at the same time.
In weapons with two completely separate systems using different cartridges and each having its own respective breech which is independent of the breech of the other system (also see U.S. Pat. No. 1,487,801), each system is naturally equipped with its own trigger.